Emperors are one of the penguin species thought to be at long-term risk from climate change. But the remoteness and hostility of their environment, along with their habit of breeding during the Antarctic winter, makes study difficult.

A major breakthrough is a new method of counting the penguins from space, made possible by scientists from the British Antarctic Survey, University of Minnesota/National Science Foundation, Scripps Institution of Oceanography and the Australian Antarctic Division. It marks the first comprehensive census of a species taken from space.

Previously, these researchers used low-resolution satellite images to locate penguin colonies, which stand out because the birds’ activity leaves brown “stains” at their colonies on the pure white fast sea ice where they breed. Once these colonies were located, researchers were able to zoom in and use high-resolution satellite images to perform an accurate count. They counted 595,000 birds, almost doubling the previous estimates of 270,000 – 350,000 birds.

This new, comprehensive estimate of the total breeding population will provide a baseline for population studies, an important foundation for ecological studies to determine how they may be affected by a changing climate.